[avalanche] Don't ban a peer sending a proof with an unknown utxo

Summary: It is possible for a peer to send a proof with a utxo from a block we don't have yet, especially after IBD completed since the latch is set after we got a block with time in the last 24h.

Test Plan:

ninja all check-all

Reviewers: #bitcoin_abc, sdulfari

Reviewed By: #bitcoin_abc, sdulfari

Subscribers: sdulfari

Differential Revision: https://reviews.bitcoinabc.org/D11815